THE SILVER INSTITUTE LETTER
VOLUME III, Number 5,
May 1973
SILVER CLEARS UP POLLUTED WATER
Russian scientists
working on water recycling and purification problems
for the Soviet space
ship and orbiting station program have decided on
silver as the best
long-term sanitizing agent. Researching the problems
of water storage over
periods of several months, as well as purification
for immediate use, they
determined that ionized silver provides the
safest and longest lasting method
of transforming polluted waste in
potable water.
A significant fact
in support of their decision to use silver for
purification was their
experimental confirmation of the absence of
toxicity in the silver treated
water. In lengthy experiments on animals
they found that 100 parts and 200
parts of silver per billion in
drinking water does not accumulate in the
organism and does not produce
any detrimental effect on the functioning of
the organs or systems of
the experimental animals.
This was also confirmed
by year long experiments on volunteer human
subjects. The concentration of
silver used in these tests . . . 100
parts and 200 parts per billion . . . is
in striking comparison with the
10 to 50 parts per billion of silver found in
potable water and in
swimming pools treated by silver purification systems in
the United
States.
The scientists, Drs.. S. V. Chizhov. S. P. Pak, N.
N. Sitnikova and Y.
U. Koloskova. tried many methods of purifying regenerated
water but all
except the silver system proved unsatisfactory over the long
run.
Ultra-violet rays and ultra-high-frequency sound reduced
micro-organisms
by as much as 97% but water thus treated failed to meet
standards of
acceptibility if the water were stored for any considerable
period of
time. Chlorine, which is widely used to kill bacteria, requires
dosages
in thousands of parts per billion compared to the 100 ppb and 200
ppb
used in the Russian tests; the chlorine itself is a pollutant
for
certain water uses and it often is dangerous to store or handle. In
sum,
the Russians found silver to be the safest sterilizing agent,
stable,
and long-lasting.
The research also showed that decontaminated
water may change in
reaction to its container. They concluded that
polyethylene containers
are suitable for the short-term storage of
silver-ionized water. For
long-term storage of a few months or more, they
decided it is better to
use a vessel made of polymers of the fluorine plastic
group, or metal
containers of vitreous enameled aluminum alloy (for lightness
in a space
ship).
Included among the many experiments conducted by Dr.
Chizhov and his
associates were those designed to assay the purification of
water
condensed from the atmosphere inside a simulated space vehicle.
The
quantity of microorganisms in the regenerated water before
the
introduction of the ionized silver varied from 200 to
1,900
microbiological parts per milliliter. Tests of the water made 15 to
20
minutes after contact with the ionized silver showed in most cases
that
in this 15 to 20 minute period, full sterilization had occurred. In
a
few cases, complete purity was achieved only after 30 to 40 minutes
of
exposure. Study of controlled samples of the water after 24 to 72
hours
showed the continned and complete absence of microorganisms.
The
Russians also suggested that the regeneration of water from the
byproducts of
human activity seems feasible through the use of silver
ions as the
decontamination agent. In this application they found it
desirable to
introduce silver ions into the water with the aid of
various filtering
materials in order to provide the slow dissolving of
the silver. Designing
the filter and selecting the form in which silver
is introduced will allow
engineers to establish any desired
concentration of silver ions in a given
volume of water, they believe.
Pioneers' Use of Silver